Snow tire with retractable studs

ABSTRACT

A tire, particularly for operation in icy conditions which has studs that are mounted so they can be retracted or extended pneumatically without changing the external configuration or shape of the tire, and can be extended without utilizing any external pressure sources.

United States Patent Anderson [451 June 27, 1972 [54] SNOW TIRE WITHRETRACTABLE STUDS [72] Inventor: James R. Anderson, Minneapolis, Minn.

[73] Assignee: Research Incorporated, Minneapolis,

Minn.

[22] Filed: May 15, 1970 [211 Appl. No.: 37,745

[52] U.S. Cl ..152/208 [51] 1nt.Cl. ..B60c 11/16 [58] Field of Search..152/208 [56] References Cited UNITED STATES PATENTS 3,516,466 6/1970Smit ..152/208 2,888,056 5/1959 Zahlten 152/208 3,095,918 7/1963 Mike152/208 3,340,921 9/1967 Garfinkle ..152/208 2,781,813 2/1957 Ferguson..l52/208 2,941,566 6/1960 Prince -152/208 FOREIGN PATENTS ORAPPLICATIONS 688,026 5/1930 France ..l52/208 Primary Examiner-Drayton E.Hoffman Attorney-Dugger, Peterson, Johnson & Westman [57] ABSTRACT Atire, particularly for operation in icy conditions which has studs thatare mounted so they can be retracted or extended pneumatically withoutchanging the external configuration or shape ofthe tire, and can beextended without utilizing any external pressure sources.

4 Claims, 6 Drawing Figures PATENTEDJunm m2 v SHEET 10F 2 I N VEN TOR.JAMES R. ANDERSON v fi fifiqjj f PATENTED I972 3.672.421

sum 20F 2 l N VEN TOR.

113mm RANDER'SON Aq-wwys SNOW TIRE WITH RETRACTABLE STUDS BACKGROUND OFTHE INVENTION 1. Field of the Invention The present invention hasrelation to tires, and more particularly to the extension and retractionof traction studs mounted in the tires.

2. Prior Art In the prior art, there have been tires that have utilizedstuds or projections that extend beyond the normal tread of the tire togive added traction. For example, U.S. Pat. No. 2,2l7,l22 discloses atire which has lugs or studs that can be projected from the exteriorsurface of the tire when desired by inflating certain pockets in thetire and deflating other pockets to change the silouette of the tire sothat the studs will project beyond the outer tread portion.

This involves therefore the changing of the cross sectional shape of thetire, giving different handling characteristics, and furthcr requiresthe use of a pressure source to extend the studs because pockets in thetire have to be inflated in order to have the studs extended.

In recent years the use of studs has been increasing at a startlingrate. Actually the studs are needed perhaps only percent of the time,even in winter. However, the studded tires are left on the car allwinter in cold areas, and the road damage from the studs has become anexpensive problem.

SUMMARY OF THE INVENTION The present invention relates to a tirestructure which has extendable and retractable traction increasing studswherein the studs can be extended quickly and easily for use whenneeded, and retracted for normal driving conditions even in winter. Thestuds therefore are used only when necessary and are usually retractedto minimize road surface damage. The present invention relates to astructure which permits the extension of the studs pneumatically, andwithout requiring a separate air source for extending the studs. Thispermits the use of the studs instantly and at any location when they arenecessary. The unit is fail-safe so that if the means holding the studsretracted loses pressure, the studs will extend, and this means that iffailure occurs the driver will have the traction advantage of a studdedtire.

It is further disclosed that the number of studs can be al tered asdesired, and two forms of studs can be utilized. One is a staple type,and the other is a headed type, both of which are mounted on wallsvulcanized on the inside of the tires, and with control tubes positionedso that when the tubes are inflated at a pressure greater than that ofthe interior tire pressure, the studs will be retracted, and when thecontrol tubes are deflated to a pressure lower than that inside a tire,the studs will start to extend. The amount of stud extension can becontrolled by the pressure differential between the stud control tubes,and the interior tire pressure.

Further the present invention includes the use of a valving arrangementto control stud extension from the driver's seat. As shown, anelectromagnet mounted on the frame of the car can be energized by thedriver to open a magnetically controlled valve controlling pressure inthe stud control hoses each time the tire rotates, and then by adjustingthe length of time the electromagnet is energized, and therefore thenumber of times that the valve is operated (it is operated once eachrevolution of the tire). The driver can automatically control theextension of the studs in his tires from the dashboard of the car.

It is therefore an object of the present invention to present a tireutilizing retractable traction increasing studs operable in response toair pressure. It is a further object to present a tire in which studscan be retracted and extended without changing the normal tire crosssection.

It is a further object of the present invention to present extendableand retractable traction studs in combination with an automobile tirethrough the use of pressure differential actuation in a single wall tirecasing.

It is a still further object of the present invention to present a tirehaving extendable and retractable studs wherein the amount of extensionand retraction can be controlled and such control can be effected fromthe dashboard of an automobile.

It is a still further object of the present invention to present a tirehaving extendable and retractable studs that is easy to manufacture.

Other objects are inherent in the description and will be apparent asthis description proceeds.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a tireshowing a typical tread having extendable and retractable studs madeaccording to the present invention and installed thereon;

FIG. 2 is a sectional view taken as on line 2-2 in FIG. 1 showing atypical installation for the staple-type stud made according to thefirst form of the present invention with the studs retracted;

FIG. 3 is a sectional view of the device of FIG. 2 with the studsextended fully;

FIG. 4 is a schematic representation of an electromagnetic actuablecontrol valve and energizing circuit;

FIG. 5 is a sectional view of a tire showing a modified form of thepresent invention installed therein where individual studs are used; and

FIG. 6 is a fragmentary perspective view of the interior structure ofthe tire of FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. I, a snow tireillustrated generally at 10 is shown mounted onto a rim or wheel 11 thatin turn is mounted onto an automobile in the usual manner. The tire 10is formed of the usual casing and has a road engaging wall having atread 12 that can be a snow grip tread, as that shown, or can be anydesired tread that is wanted. The tire itself has the usual airinflation valve shown schematically at 13. The casing includes sidewalls l4, l4 joining the road engaging wall and of course the bead ofthe tire 15 that seats within the rim.

Adjacent the road engaging wall of the tire and on the interior, thereis a multiple layer fluid tight barrier wall 16 that extends between theside walls l4, l4 and is sealingly vulcanized or joined to two of theinterior surfaces of the side walls 14, 14 along annular lines indicatedat l7, 17 on opposite sides of the tire adjacent the outer portions ofthe tire where the tread is formed. The barrier wall 16 divides theinterior of the tire into two separated chambers. The barrier wall isformed, as shown, of at least two layers of material that can either beelastomeric, fabric reinforced elastomers, or some other type ofsynthetic or natural material that is fluid tight. The barrier wall isdeflectable but somewhat rigid to distribute pressure forces. Severallayers can be used to form the wall 16 if desired.

A plurality of individual staple type studs 20 are mounted to thisbarrier wall 16 and move therewith. The studs are made of suitable hardmetal and are positioned on the barrier wall 16 so that they will alignwith a pass through provided openings 21 extending through the treadwall or tread portion of the tire to the exterior of the tire. Each ofthe stud staples 20 has a pair of legs 22, 22 forming the projectingstud means and a cross member or base member 23 that is held in thebarrier wall 16. Between the legs 22, 22 of each of the staple studs 20,and positioned between the interior surface 24 of the road engagingtread wall of the tire and surface 25 of the barrier wall there is anair tight tube made up of several elastomeric or stretchable inflatabletube sections 26. The outer edge tube sections 26 are positionedannularly around the tire. The outer tube sections extend between thelegs 22 of all of the studs that the tube section is aligned with. Thelegs 22 are positioned in annular rows, or can be offset slightly, sothe tube sections have to snake back and forth slightly. The outer tubesections 26 are connected together with a center tube section 26A that,as shown, spirals around the interior of the tire between the outer tubesections 26. Cross tubes extending directly across the tire between theouter tube sections can be used for pneumatically connecting the outertube sections 26, but the spiralled center section makes it easier tobalance the tire. All of the studs are positioned so their legs are onopposite sides of one of the tube sections 26. The tube sections 26 thusextend around the tire to control all of the staple type studs.

The tube sections 26 and 26A are joined together with fluidcommunication between the interiors of each of the tube sections andthey form a continuous tube assembly. A pressure valve illustratedgenerally at 30 will permit inflating the interior of all of the tubesections and consequently control the amount of inflation of the tubesections 26 for all of the studs. The barrier wall 16 forms an interiorinflation chamber in the tire holding inflation pressure. The wall 16could also be termed a bladder wall.

It should be noted that valve assembly 30 in the first form of theinvention is positioned so it is not necessary to run any tube sectionthrough the barrier wall.

The valve assembly 30 can be of any usual or preferred type, which willpermit inflation of the tube sections 26 and 26A so that the tubesections can expand into the configuration shown in FIG. 2. When thetube sections 26 are inflated to a pressure wherein the pressure insideof the main tire chamber between the side walls 14, and designated I isless than the pressure on the interior of the tube sections, designatedP the barrier wall 16 will be pushed away from the surface 24 in theseareas against the force from the tire inflation pressure, and at thesame time the staple type studs will be moved inwardly. The legs 22, 22of each the studs will slide inwardly in their provided openings 21until the tubes 26 reach the condition where they are expandedsufflciently to retract the studs the desired amount. If the tubesections are fully expanded the studs completely retract and the tirewill merely run along its outer tread or road engaging surface withoutany stud action. The amount of retraction available will be selected topermit stud retraction even after normal tread wear. The barrier wall islimber enough to deflect without changing the tire casing profile.

When the valve 30 is opened to deflate all of the tube sec tions 26 and26A, the pressure P, acts against the barrier wall, which has somestiffness to give a surface area on which the pressure P acts to provideforce to push the studs out.

FIG. 3 shows all of the tube sections 26 and 26A collapsed flat, andthis is after the valve 30 has been opened to fully deflate the tubesections. The legs 22 forming the stud means are fully extended for use.

It should be noted that by controlling the pressure P, in the tubesections 26 in relation to P,, the pressure inside the main tirechamber, the size of the tube sections 26 can be controlled so that theamount of extension of the studs can be controlled. The studs can bemade to just barely protrude beyond the tread of the tire, or protrudeto their full extent as shown in FIG. 3. The tube sections 26 extendingbetween the legs of the staple type studs insure that the studs will notpull out of the barrier wall 16 but will be actuated directly on theirbase members 23 when the tube sections are inflated for retraction.Again, the device is a fail-safe unit in that all that needs to be donewhen the studs are to be used is to deflate the tube sections 26, and noinflation is necessary. When the studs are to be retracted, aconventional service station pressure hose can be utilized for inflatingthe tube sections 26 and retracting the studs.

The valve 30 may be the usual tube valve type for manual deflating ormay be of a special type, if desired, that can be actuated by a magneticflux adjacent the valve. Several types of valves can be used, and forillustrative purposes a simple poppet valve that is spring loaded to itsclosed position with a slidably mounted flanged actuating disc at oneend, and wherein the disc operates in a chamber and is spring loaded toclosed position is shown schematically. The interior stern supportingthe poppet valve is constructed like a conventional tire valve forinflation. The valve unit can be vulcanized in the side wall of the tireadjacent the thread wall as shown. The valve unit can be quite small.Then an electromagnet can be mounted on the auto frame portion 39 andpositioned so that it will align with the path of movement of the valveas the tire rotates. When the electromagnet is energized it will createa magnetic flux that will act on the valve to pull the poppet away fromits seat and let air escape from the tube sections 26.

As shown schematically in FIG. 4, a small housing 35 is utilized thishousing is vulcanized into the tire wall and may have a plastic interiorsurface. A sliding flanged disc 36 is mounted inside the housing and isspring loaded with a spring 37 to force a poppet valve 38 against a seatconnected to the end of tube sections 26. The spring 37 is sufficientlystrong to keep the valve closed at maximum pressure in the tube sections26. When the field of magnetic flux from the electromagnet indicatedschematically at 40 acts on the disc 36, (which has at least portionsthereof that are attracted by the electromagnet) the disc will slidetoward the electromagnet against the action of the spring 37, and willpull the poppet away from the valve seat, to let air escape out throughthe poppet valve and through openings in disc 36 to atmosphere.Electromagnet 40 is mounted onto a frame section 39 of the car adjacentthe tires (one on each side) and is controlled by a switch 41 mounted onthe dashboard of a car and energized by the car battery 42. When theswitch 41 is closed, the electromagnet is energized and each time thetire rotates past the electromagnet the poppet valve 38 would be pulledaway from its seat for a short period of time letting a little bit ofair out of the tube sections 26. This air will escape to atmospherethrough holes in the disc 36. The disc 36 could be replaced with amagneti cally deflecting diaphragm that was biased to a valve closedposition. By holding the electromagnet energized for the desired lengthof time, the desired amount of air can be permitted to escape from thetube sections 26 so that the studs can be extended the desired amountbefore the switch 41 is again opened. This can be done by the operatorof the automobile simply by pushing a switch on the dash. Note thatwhile only one magnet is shown, there would be one for each of the tireshaving the retractable studs.

Of course the spring 37 has to be sufficiently strong so that the poppetvalve will seal the tube sections 26 during normal operation, even whenthe desired amount of pressure is being carried in the tube sections 26,and yet balanced enough so that the force from the electromagnet willcause proper actuation of the member 36.

If an electromagnetic valve such as that shown schematically in FIG. 4is utilized, a separate conventional air inflation valve 30 can beutilized for filling the hoses and retracting the studs after they haveonce been extended. Alternately, as shown, the center 43 of the poppetsupport stem can be formed as a conventional tire valve to permitinflation, and also deflation manually. The end of the valve protrudesbeyond disc 36 so it is accessible for use.

A modified form of the invention is shown in FIG. 5 and 6, but thegeneral principle still is the same. However, in this form of theinvention the tire 45 is mounted again onto a rim and has a suitable airinflation valve 13 for inflating the interior of the tire, and has atread wall as in the previous form of the invention. However in thisform a deflectable barrier wall or bladder member 46 is sealinglyvulcanized along the side walls of the tire to divide the tire into twosections, and is utilized for embedding the heads of individual studs 47that are arranged in annular rows around a tire as shown or can bepositioned as desired. Between the rows of studs 47, there arepositioned flexible air tight tube sections 48 which are fluidlyconnected together with suitable cross passages on which can be acontinuous tube wound in a spiral and offset between each of the annularrows of studs 47. The tube sections 48 can be vulcanized into thebladder or barrier wall if desired. The tube formed from the tubesections 48 is closed at one end and includes an extension coming downthrough the interior of the tire sealingly passing through the barrierwall 46 and carried out through the rim supporting tire. A tire valve 49of conventional design controls fluid passage to the interior of thetube sections. The tube sections 48 can be inflated, and when the tubesections are inflated to a pressure greater than the pressure inside themain part of the tire 45, the barrier wall 46 will be deflected awayfrom the interior surface 50 of the tread wall of the tire to positionshown in FIG. 5, and the studs 47 are retracted. By deflating the tubesections 48, again, the interior tire pressure against the inside of thebarrier wall will force the barrier wall 46 up against the surface 50and the studs would thus be extended to position as shown in dottedlines.

In FIG. 6, the barrier wall 46 is shown removed from the tire casing inperspective view to show the plurality of studs 47 extendingtherethrough in annular rows. The studs extend through providedapertures in the treads ofa tire for extension or retraction through theuse of an inflatable and deflatable tube section between the interiorsurface of the tread portion of the tire and the barrier wall to controlmovement of the barrier wall in and out and thus control movement of thestuds in and out. Also, in this form the barrier wall is flexible butsomewhat stiff or rigid to give adequate force on the studs, but stillbe able to move as needed without changing the tire casing crosssectional shape.

It should be noted that the openings 21 for the legs 22, and theopenings for the studs 47 permit air to bleed past the studs, so thatthe barrier walls will move relative to the interior surface of thetire, and no vacuum will be created and no problems with deflation ofthe tube sections used for controlling the studs will be encountered.The barrier walls in both embodiments seal the normal interior space fortire inflation.

ln both forms of the invention the operation of the studs is fail-safe,meaning that the studs are extended whenever the tube sectionscontrolling the studs will leak or be deflated for any reason. Studs canbe extended any place as soon as they are needed because deflation isthe method of extension of the studs. The stud extension distance can bechanged by controlling the differential between the interior tirepressure (P,), and the control tube pressure (P The extension force isachieved by the use of the internal tire pressure against the relativelystiff internal barrier wall which will force the studs outwardly. Thebarrier wall is flexible enough for movement but has some stiffness togive a sufficient force to extend the studs and hold the studs inextended working position even when supporting an automobile.

The volume of air in the tubular sections relative to the total volumeof air in the tire is very small. Thus inflating or deflating the tubesections does not affect the tire inflation pressure to any substantialdegree.

What is claimed is:

1. In combination, a vehicle, a wheel rotatably mounted on said vehicle,a tire mounted on said wheel and holding interior inflation pressure inan interior tire chamber, said tire comprising a casing with side wallsand a road engaging wall having a road engaging surface and an interiorsurface, a deflectable barrier wall sealingly dividing said interiortire chamber from the interior surface of said road engaging wall, aplurality of traction stud means slidably mounted through said roadengaging wall, means to mount said stud means to be movable with saidbarrier wall from an extended position wherein said stud means extendoutwardly beyond the road engaging surface of said tire to a retractedposition, tubular expandable inflatable means acting between theinterior surface of said road engaging wall and said barrier wall tocontrol movement of said barrier wall and said stud means with respectto said road engaging wall in response to pressure differentials betweensaid tubular expandable inflatable means and the interior tire chamber,and electromagnetically actuated valve means for relieving pressure insaid tubular, expandable inflatable means, an electromagnet mounted onsaid vehicle adjacent the path of movement of said tire, and remoteswitch means for actuating said electromagnet to operate said valve torelieve pressure in said tubular inflatable means.

2. in combination, a vehicle, a wheel rotatably mounted with respect tosaid vehicle, and a tire having a casing with a tread wall having anouter surface and mounted onto said wheel and holding inflationpressure, a barrier wall sealed to the interior of said casing to form atire inflation chamber and a second chamber adjacent the tread wall ofsaid tire, said barrier wall being unattached with respect to theinterior of said tire in at least certain portions adjacent said treadwall and being deflectable in at least some of said unattached portions,a plurality of stud means mounted to said barrier wall, said stud meansextending through openings provided in said tread wall, and separateinflatable means between said barrier wall and an interior surface ofthe tread wall of said tire, in at least some of the unattached portionsof said barrier wall, said separate inflatable means being capable ofbeing inflated to a size sufficient to deflect portions of said barrierwall away from said tread wall against the inflation pressure in theinflation chamber to retract stud means carried by said barrier wall sothat said stud means do not protrude beyond the outer surface of saidtread wall, said separate inflatable means being deflatable to aposition wherein said stud means will extend outwardly beyond the outersurface of the tread wall of the tire, and valve means for said separateinflatable means located adjacent a side wall of said tire, said valvemeans including an element movable under magnetic force to a deflationposition wherein it will permit air to escape from said inflatablemeans, and electromagnet means mounted on said vehicle adjacent to saidtire and positioned to create a flux capable of actuating said valvemeans to a deflation position, said electromagnet being controllable byan operator of said vehicle.

3. The combination as specified in claim 2 wherein said separateinflatable means comprise tubular members between the barrier wall andthe interior of the tread wall of the tire said tubular members beingpositioned closely adjacent the stud means and all tubular members beingin fluid communication.

4. The combination as specified in claim 3 wherein said stud meanscomprise staple type studs having a pair of legs and a base member, saidbase members being attached to said barrier wall, and said tubularmembers passing between the legs of each of the staple type studs.

1. In combination, a vehicle, a wheel rotatably mounted on said vehicle,a tire mounted on said wheel and holding interior inflation pressure inan interior tire chamber, said tire comprising a casing with side wallsand a road engaging wall having a road engaging surface and an interiorsurface, a deflectable barrier wall sealingly dividing said interiortire chamber from the interior surface of said road engaging wall, aplurality of traction stud means slidably mounted through said roadengaging wall, means to mount said stud means to be movable with saidbarrier wall from an extended position wherein said stud means extendoutwardly beyond the road engaging surface of said tire to a retractedposition, tubular expandable inflatable means acting between theinterior surface of said road engaging wall and said barrier wall tocontrol movement of said barrier wall and said stud means with respectto said road engaging wall in response to pressure differentials betweensaid tubular expandable inflatable means and the interior tire chamber,and electromagnetically actuated valve means for relieving pressure insaid tubular, expandable inflatable means, an electromagnet mounted onsaid vehicle adjacent the path of movement of said tire, and remoteswitch means for actuating said electromagnet to operate said valve torelieve pressure in said tubular inflatable means.
 2. In combination, avehicle, a wheel rotatably mounted with respect to said vehicle, and atire having a casing with a tread wall having an outer surface andmounted onto said wheel and holding inflation pressure, a barrier wallsealed to the interior of said casing to form a tire inflation chamberand a second chamber adjacent the tread wall of said tire, said barrierwall being unattached with respect to the interior of said tire in atleast certain portions adjacent said tread wall and being deflectable inat least some of said unattached portions, a plurality of stud meansmounted to said barrier wall, said stud means extending through openingsprovided in said tread wall, and separate inflatable means between saidbarrier wall and an interior surface of the tread wall of said tire, inat least some of the unattached portions of said barrier wall, saidseparate inflatable means being capable of being inflated to a sizesufficient to deflect portions of said barrier wall away from said treadwall against the inflation pressure in the inflation chamber to retractstud means carried by said barrier wall so that said stud means do notprotrude beyond the outer surface of said tread wall, said separateinflatable means being deflatable to a position wherein said stud meanswill extend outwardly beyond the outer surface of the tread wall of thetire, and valve means for said separate inflatable means locatedadjacent a side wall of said tire, said valve means including an elementmovable under magnetic force to a deflation position wherein it willpermit air to escape from said inflatable means, and electromagnet meansmounted on said vehicle adjacent to said tire and positioned to create aflux capable of actuating said valve means to a deflation position, saidelectromagnet being controllable by an operator of said vehicle.
 3. Thecombination as specified in claim 2 wherein said separate inflatablemeans comprise tubular members between the barrier wall and the interiorof the tread wall of the tire said Tubular members being positionedclosely adjacent the stud means and all tubular members being in fluidcommunication.
 4. The combination as specified in claim 3 wherein saidstud means comprise staple type studs having a pair of legs and a basemember, said base members being attached to said barrier wall, and saidtubular members passing between the legs of each of the staple typestuds.